The Movement of Botulinum Toxin Through the Lateral Gastrocnemius Muscle in Humans: An Expanded Examination: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for The Movement of Botulinum Toxin Through the Lateral Gastrocnemius Muscle in Humans: An Expanded Examination (NCT03367429), a randomized phase 4 study. The primary outcome is Botulinum Toxin Muscle Effect (BTME) Volume of Abnormal Voxels Per MRI Slice in Muscles After Research Injections.

2. Clinical Question

The study’s stated purpose was methodological as well as clinical: to refine an MRI approach for visualizing botulinum toxin movement through muscle, and to explore whether spastic muscle and different dilutions affect that movement. The registry summary describes the rationale as a need for better understanding of toxin movement and better research techniques. It does not report a completed comparison of injection dilutions or a result about movement into other muscles.

The planned MRI endpoint was a measure of abnormal-voxel volume, not a direct clinical measure of change in spasticity or function. The registry also lists a secondary outcome concerning change in abnormal-voxel volume after clinical injections. No secondary outcome result is reported. The record states that Experiment 1 did not yield enough participants or data to proceed with experiments 2 and 3, so the planned primary question remains unanswered by the posted results.

3. Trial Design

The registry classifies NCT03367429 as a randomized, unmasked, parallel study and lists it as Phase 4. The listed enrollment is 4. The record gives a start date of 2018-06-15, a primary completion date of 2019-09-18, and a terminated status. Those design labels should be read alongside the arm descriptions: they describe possible designs for experiments 2 and 3, and the registry states that those experiments did not proceed because Experiment 1 did not yield enough participants or data.

The planned arms concerned Botox injections using different saline dilutions. In the description for Exp 2 & 3 - Arm 1, the experimental injection was 25 units diluted in 0.50 cc of saline to the spastic LGM, while the standard injection was 25 units diluted in 0.25 cc of saline to the spastic MG. The other arm description reverses the planned experimental and standard injections across the muscles, though its description of the muscle for the experimental injection is incomplete. Both descriptions are conditional on a within-subject design being adopted. The registry also mentions that either a within-subject or between-subject design was under consideration.

Consequently, the registry’s randomized and parallel classifications do not establish which design, if any, was implemented for the experiments planned to measure the primary endpoint. The injection assignments actually used in Experiment 1 are not fully specified by the information in the record. Masking was listed as none. Details about allocation procedures, eligibility, recruitment, adherence, and the statistical plan are not reported in the registry record.

The study dates and terminated status describe the administrative record, not completion of the intended endpoint assessment. The stated primary endpoint timeframe was MRI 2, 2 Months after Research Injection, but the record explicitly says the data were never collected. Thus, the listed design is useful for understanding the intended research question, but it does not describe a completed efficacy-style comparison with endpoint estimates.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Before assignment: We are unable to locate the data for one subject.

Overall Study

Analysis population for the primary outcome, as defined in the registry: The data was never collected since Experiment 1 didn't yield enough participants or data to proceed with either a within subject or between subject study design for experiments 2 and 3.

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

Population: there were no participant enrolled in ARM 1.

6. Primary Endpoint

The registry lists the primary outcome as Botulinum Toxin Muscle Effect (BTME) Volume of Abnormal Voxels Per MRI Slice in Muscles After Research Injections, measured over At MRI 2, 2 Months after Research Injection.

The primary endpoint was Botulinum Toxin Muscle Effect (BTME) volume of abnormal voxels per MRI slice in muscles after research injections. The registry describes calculating BTME volume by counting abnormal voxels on MRI 2, taken 2 Months after Research Injection. Each voxel volume is .0015 cc. A voxel was classified as abnormal when its relaxation time was greater than or equal to 3 standard deviations above the baseline mean for that subject and muscle, as measured on baseline MRI.

As a statistical measure, the endpoint converts MRI signal information into a count-based measure of volume. A prespecified threshold can make an imaging measure more reproducible by defining which voxels contribute to the outcome. The baseline-based threshold also anchors the classification to each subject’s and muscle’s starting MRI measurement, rather than relying on a single threshold for everyone. These are general features of threshold-based imaging outcomes; they do not establish that the measure was validated or that it captures every aspect of toxin movement.

The registry’s rationale was to refine a non-invasive MRI technique for visualizing intramuscular effects. Such an endpoint is relevant to that methodological aim because it is based on MRI rather than on a reported clinical symptom. It is not, by itself, a measure of clinical benefit, function, or safety. The record does not provide an endpoint value, unit summary, dispersion measure, or analysis result. Most importantly, it states that the data were never collected because Experiment 1 did not yield enough participants or data for experiments 2 and 3. The planned MRI measure therefore cannot be interpreted as an observed treatment effect in this study.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The following statistical concepts are general explanations, not additional findings from the study. They help distinguish what the registry planned from what the posted results actually establish.

What does randomization contribute?

Randomization is intended to make assignment to study conditions independent of measured and unmeasured participant characteristics, on average. In a completed trial, that can support interpretation of a between-condition contrast, provided the design is implemented as planned and the analysis respects the assignment. The registry labels this study randomized, but the primary endpoint was never collected and the planned experiments 2 and 3 did not proceed. The label therefore does not produce a randomized estimate in the absence of outcome data.

The record also lists a parallel model and no masking. A parallel design generally assigns participants to a study condition that is compared with another condition. A within-subject design instead compares conditions within the same participant. These designs have different structures and require analyses that reflect how observations are related. The arm descriptions are conditional on adopting a within-subject design, while the registry also refers to a possible between-subject design. The design actually used for the uncollected primary endpoint is not reported.

How should the MRI threshold be understood?

The endpoint definition uses a baseline mean and a standard-deviation threshold for each subject and muscle. In general, standard deviation describes the spread of measurements around a mean. Setting a threshold relative to baseline can define which later MRI voxels count as abnormal for the endpoint. The registry specifies that the voxel relaxation time must be greater than or equal to 3 standard deviations above the baseline mean. It also specifies that each voxel volume is .0015 cc and that the count is taken on MRI 2, 2 Months after Research Injection.

Thresholding simplifies a continuous imaging signal into a classification used for counting. That can make the endpoint easier to define, but the result depends on the threshold rule and the quality and comparability of MRI measurements. The record does not report validation findings, reader reliability, image-processing details, or sensitivity analyses using alternative thresholds. These details are not reported in the registry record, so the robustness of the planned measure cannot be assessed from the posted information.

What would an effect estimate and confidence interval convey?

In general, an effect estimate summarizes the contrast defined by the study question. A confidence interval communicates the range of values compatible with the data and the specified statistical procedure. A narrow interval generally indicates greater precision than a wide interval, but interpretation also depends on the measure, design, and assumptions. Since the registry reports that the primary data were never collected, there is no estimate or interval to interpret for BTME volume.

Similarly, a significance test addresses compatibility of the data with a statistical hypothesis under a model; it does not establish that a difference is clinically important. No primary-outcome test or p-value is reported. The registry lists zero analyses. Statistical significance, effect magnitude, and precision are therefore all unavailable for the planned comparison.

What do the planning assumptions mean?

In general, sample-size calculations use assumptions about the target effect, variability, significance level, allocation, and analysis method to illustrate the amount of information a future study may need. The record’s planning assumptions specify a two-sided significance level of 0.05, equal allocation, and a normal approximation, with the target effect expressed as a stated fraction of the observed effect. For non-time-to-event calculations, the intended unit is participants per arm; for time-to-event calculations, it is total events.

Those are planning conventions, not observed trial outcomes. Sample-size illustrations are not observed power and cannot rescue an absent endpoint estimate. Because the primary outcome data were never collected, no observed primary effect is available from this study to anchor an effect-based planning illustration. Actual planning output values and a sample-size justification for the trial are not reported in the registry record. The registry also does not report whether any interim analyses were planned or conducted.

Why does over-dispersion matter in general?

For count outcomes, a statistical model may assume a particular relationship between the mean and variability. Over-dispersion means the observed variability is greater than the model assumes. If ignored, standard errors may be too small and intervals or tests may appear more precise than warranted. This is a general consideration for count-based outcomes, not a reported problem in this study. The registry gives no BTME data from which to assess the distribution, variability, or over-dispersion of the planned outcome.

Overall, the registry supplies an endpoint definition and some design and planning assumptions, but not an analysis plan detailed enough to establish how the primary outcome would have been modeled. The actual endpoint data and analyses are absent. Accordingly, statistical method descriptions can clarify the intended measurement and general reasoning, but cannot yield a study-specific estimate.

10. Multiplicity, Missing Data and Analysis Populations

The registry does not report a multiplicity plan. Multiplicity is a general concern when a study evaluates several outcomes, comparisons, time points, or analysis choices: the more opportunities to declare a finding, the greater the chance of a false-positive result if testing is not addressed appropriately. The record lists a primary endpoint and a secondary outcome concerning change in BTME volume after clinical injections, and it reports two outcome measures. It does not describe a testing hierarchy, adjustment procedure, or other multiplicity strategy. With no outcome data or analyses reported, there are no study-specific tests whose multiplicity can be evaluated.

The primary outcome population description states that the data were never collected because Experiment 1 did not yield enough participants or data to proceed with experiments 2 and 3. This is different from ordinary participant-level missingness within a completed outcome assessment. The record does not give a set of observed primary outcomes with some values missing; it says the planned primary data were not collected. It therefore does not support assumptions about the pattern or mechanism of missing observations, or an imputation analysis.

Methods for handling missing data, deviations from assignment, and incomplete follow-up are not reported in the registry record. The analysis population is also not reported: there is no stated intention-to-treat, per-protocol, or other population for a primary endpoint analysis. The registry lists zero analyses, so there is no analysis set to characterize and no sensitivity analysis to assess.

These omissions limit what can be said about the intended analysis, but they do not alter the direct reason the primary result is unavailable: the endpoint data were not collected for the planned experiments. No missing-data adjustment or multiplicity correction can create an observed outcome contrast when the relevant data are absent.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

The registry reports serious adverse events and other adverse events in groups associated with the planned experiments. For Exp 2 & 3 - Arm 1 and Exp 2 & 3 - Arm 2, the reported at-risk counts are 0, with 0 serious events, 0 other events, and 0 deaths. Because the at-risk count is 0 for these groups, the figures do not provide an exposure-based safety estimate for the planned later experiments.

For Exp 1 - Arm Unknown, the registry reports 1 at risk, 0 with a serious event, 0 with another event, and 0 deaths. For Exp 1 Arm 1, the reported at-risk count is 0 and all reported event counts are 0. For Exp 1 - Arm 3, the reported at-risk count is 2, with 0 serious events, 0 other events, and 0 deaths. The record gives the same adverse-event figures for Exp 1 Arm 2 as for Exp 1 - Arm Unknown: 1 at risk and 0 affected for serious events, other events, and deaths.

These entries describe what the registry reports, not a comprehensive demonstration of safety. The groups have differing reported at-risk counts, some groups have no participants at risk, and the planned experiments did not proceed. The record does not provide event descriptions or serious adverse-event terms. Zero reported events in these entries should not be generalized beyond the recorded groups and circumstances.

12. What the Result Does, and Does Not, Mean

The record establishes that the study was intended to refine an MRI technique for examining botulinum toxin movement through muscle and to explore possible effects of muscle type and dilution. It also establishes the planned primary measure: MRI-based BTME volume defined by abnormal-voxel counts at a specified follow-up. Those are descriptions of the research question and measurement plan, not findings about the biological effect of the injections.

The most important boundary is that the primary outcome data were never collected. Experiment 1 did not yield enough participants or data to proceed with experiments 2 and 3. As a result, there is no posted estimate comparing the experimental and standard dilutions, no estimate of MRI-measured toxin movement, and no statistical uncertainty measure for the planned endpoint. The registry lists no analyses.

The record does not show that the experimental dilution produced a larger or smaller MRI effect than the standard dilution. It does not establish whether spastic muscle changes toxin movement, whether the imaging method reliably detects movement, or whether the planned MRI measure corresponds to a clinical change. It also does not report a completed evaluation of movement into non-injected muscles. The study’s rationale discusses these topics, but rationale and planned aims are not equivalent to observed results.

The safety entries are similarly limited. They report no affected participants in the listed adverse-event fields, but some experiment groups have no participants at risk and the planned later experiments did not proceed. Those figures cannot establish a general safety profile.

Thus, the posted record is informative about why the intended primary comparison is unavailable and how the endpoint was defined. It is not evidence for or against a treatment effect. The terminated status and lack of endpoint data should be distinguished from a completed trial with a null finding: no null estimate was reported, because the relevant outcome was not collected.

13. Why This Trial Matters Statistically

This study illustrates a distinction that is central to clinical-trial interpretation: a clearly defined endpoint is not the same as an observed endpoint. The registry specifies an MRI-based measure, its threshold rule, voxel volume, and intended assessment time. Those details let readers understand what the investigators planned to measure. Yet the endpoint data were never collected, so the measurement plan does not yield an estimate of toxin movement or a comparison between planned injection conditions.

That distinction matters especially in early or method-focused research. The registry’s stated aim was to refine non-invasive MRI measurement and explore factors that might affect toxin movement. Method development can be valuable, but its claims depend on actual measurement data, reproducibility information, and an analysis capable of addressing the intended question. None of those outcome results are reported for the planned primary endpoint in this record.

The record also demonstrates why design labels should be read with the arm descriptions and study status. Randomized and parallel are the listed classifications, but the descriptions discuss conditional within-subject and between-subject plans. The later experiments did not proceed. Reading the labels alone could imply a completed comparative analysis that the record does not contain.

Finally, the study highlights the limits of safety counts when denominators are small or absent. Zero reported events in a group with no participants at risk is not an estimate of event frequency. Counts need to be interpreted alongside who was observed and whether the planned treatment exposure took place. In this record, the adverse-event entries do not compensate for the missing primary outcome or establish a broader safety conclusion.

The statistically responsible reading is therefore focused: the registry documents an important measurement question and a planned MRI endpoint, but does not report the data needed to answer that question. Separating aims, design intentions, and observed results prevents a planned study from being mistaken for evidence of an effect.

14. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The defining limitation is the absence of primary outcome data. The registry says the data were never collected because Experiment 1 did not yield enough participants or data to proceed with experiments 2 and 3. Without those observations, the planned comparison has no effect estimate, uncertainty interval, or test result.

The design is not fully resolved by the registry descriptions. Although the record classifies the study as randomized and parallel, the descriptions for the later experiments are conditional on adopting a within-subject design, and the summary refers to either within-subject or between-subject designs. The actual design implemented for the primary endpoint is not reported. The arm descriptions also differ in which muscle receives each planned dilution, and one description leaves the muscle for the experimental injection incomplete. These details constrain reconstruction of the intended contrast.

Enrollment is listed as 4, but the record does not identify an analyzed primary-outcome population or report participant-level endpoint observations. Eligibility criteria, participant characteristics, allocation procedures, adherence, and the reasons for termination beyond the stated inability to proceed with later experiments are not reported in the registry record.

The endpoint is defined using a baseline-based MRI threshold and voxel volume, but the record provides no validation or reliability results, image-processing details, outcome distributions, or sensitivity analyses. The statistical analysis plan, missing-data methods, multiplicity handling, and analysis populations are not reported. The registry lists zero analyses.

Finally, the adverse-event figures have limited interpretability because reported at-risk counts differ by group and are zero in some planned arms. Event terms are not listed. These limitations mean the posted information supports description of the study’s aims and data-collection failure, but not a treatment-effect or broad safety conclusion.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: The Movement of Botulinum Toxin Through the Lateral Gastrocnemius Muscle in Humans: An Expanded Examination — NCT03367429.
• Registry record last updated 2021-12-29; status last verified 2021-11.
• Results first posted 2021-12-29.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

18. Record Summary

NCT03367429, “The Movement of Botulinum Toxin Through the Lateral Gastrocnemius Muscle in Humans: An Expanded Examination,” is listed as a randomized, unmasked, parallel Phase 4 study sponsored by Weill Medical College of Cornell University. The registry lists enrollment as 4, a start date of 2018-06-15, a primary completion date of 2019-09-18, and a terminated status.

The study aimed to refine an MRI technique for examining botulinum toxin movement through muscle and to explore muscle type and dilution. The primary endpoint was planned as BTME volume of abnormal voxels on MRI 2, 2 Months after Research Injection, using a threshold of greater than or equal to 3 standard deviations above the baseline mean. The registry states that the primary data were never collected because Experiment 1 did not yield enough participants or data to proceed with experiments 2 and 3.

No primary outcome analysis or effect estimate is reported. The adverse-event entries report zero affected participants in the listed fields, with differing at-risk counts across groups. The record documents the intended question and measurement plan, but does not report results answering the primary question.